As illustrated in FIG. 1A, a conventional pixel driving circuit of a typical active matrix/organic light-emitting diode (AMOLED) is implemented by a 2T1C pixel driving circuit, which includes a control transistor T, a driving transistor DTFT and a capacitor C, and is configured to drive the organic light-emitting diode (OLED). A gate electrode of the control transistor T is inputted with a control signal SW and the control transistor T is further connected to a data line DATA, a high level VDD is inputted to an anode of the OLED, and a low level is inputted to the driving transistor DTFT. Thus, the conventional 2T1C pixel circuit is quite simple in structure.
However, regarding a low temperature poly-silicon (LTPS) based AMOLED pixel driving circuit, there might be problems such as poor uniformity of threshold voltages, and thus a driving thin film transistor (TFT) threshold voltage compensation circuit is required to be integrated into the pixel driving circuit of the LTPS based AMOLED.
As illustrated in FIG. 1B, in a conventional design, a 5T2C pixel driving circuit or more TFTs and/or capacitors are required to implement the AMOLED pixel driving circuit with the threshold voltage compensation function. As illustrated in FIG. 1B, the 5T2C pixel driving circuit includes a first control transistor T1, a second control transistor T2, a third control transistor T3, a fourth control transistor T4, a first capacitor C1, a second capacitor C2 and a driving transistor DTFT, and is configured to drive the OLED. A control signal CR1 is inputted to a gate electrode of T1, a gate electrode of T2 and a gate electrode of T4. A gate electrode of T3 is connected to a scanning line SCAN, and a data voltage Vdata is inputted to T3. A first end of C1 is indicated by a reference A, and a second end of C1 is indicated by a reference B. The high level VDD is inputted to the DTFT. A low level VSS is inputted to a cathode of the OLED. With increasing of the number of the TFTs and/or capacitors, a larger and larger area in a layout region will be occupied, which may adversely affect on a decreasing of a size of the AMOLED pixel, and thus progress of an AMOLED pixel driving circuit with high pixel per inch (PPI) is restrained.